MvcWebApiCors is a small library for .NET MVC 4 which sets the response headers correctly to allow Cross Origin Resource Sharing. You don't have to upgrade to MVC 5, you don't have to upgrade to Visual Studio 2013 and you definitely don't have to have IE10!

This library will automatically proxy CORS requests (Cross-origin resource sharing) if IE9 or below is used.
The proxy is integrated in ASP.NET and works with all ASP.NET libraries like WebForms, Mvc and WebApi.
jQuery is used at the client side.